This invention relates to an optical fibre connector.
When optical fibres are used in, for example, information transmission systems, it is frequently necessary to provide a connection between a pair of optical fibres so that light can be transmitted between the fibres. With such an arrangement, a problem exists in providing a connector which ensures accurate alignment between the mutually presented end surface of the fibres but which at the same time is simple and inexpensive to manufacture.
To date, a number of solutions have been proposed to the problem of providing a simple and efficient optical fibre connector. For example, German OS No. 2717321 discloses an optical fibre connector, which in its simplest form, comprises two identical, substantially planar blocks, each of which is provided with two axially spaced, resilient, upstanding clamps which are used to grip a respective fibre in the required position on the block. Each block is also provided with an upstanding guide for the optical fibre which, in use, is gripped by the clamps on the other block and which is to be optically connected to the fibre mounted on the first-mentioned block. The guide members are arranged so that, when the two blocks are presented to each other with the fibres gripped in their respective clamps, each guide member lies between and is gripped by the two clamps on the opposing block. The blocks are thereby locked together with the two fibres being held in their correct relative orientation.
Providing dimensional tolerances are accurately maintained, a satisfactory connection between optical fibres can be made by the arrangement disclosed in German OS No. 2717321. However, any dimensional inaccuracy can cause shear stresses to be imposed on the fibres at the interfaces between the clamps and the guides. Moreover, even without such inaccuracies, stresses at these interfaces can be imposed when the two blocks are being assembled, since the interlocking arrangement is hidden from view during assembly and hence it would be simple for an operator to assemble the blocks with some slight transverse misalignment, thereby resulting in the shearing action. A partial solution to these problems can be achieved by employing the modified arrangement disclosed in DE OS No. 2717321 in which further upstanding clamping means is provided on the surface of each block where the respective fibre is mounted, but at a remote site from the fibre so that any transverse forces applied to the assembled connector will not allow this shearing action to occur. However, even this alternative arrangement is not entirely satisfactory since the additional clamping means make the connector bulky and assembly of the two blocks is still effected with the interlocking and clamping arrangements hidden from view.
A further optical fibre connector is disclosed in British Pat. No. 1586001 which, in its simplest form as shown in FIGS. 1 to 5, includes identical L-shaped blocks each of which is formed in one limb with a channel arranged to receive a respective one of the fibres to be interconnected. The other limb of each block is provided with a bore through which the associated fibre must be inserted prior to the assembly of the connector. Assembly is effected with the channels being presented to each other and with the other limbs of the blocks defining vertical mating surfaces which control the positioning of the ends of the fibres with respect to each other. The fibres are clamped between the channels to provide the required axial alignment of the fibres and elastomeric pads are provided in the channels respectively to support the fibres when the connector is assembled. In the assembled connector, the blocks are apparently held in abutment by means of a sheath provided around the assembly, although this sheath is only disclosed in relation to a more complex embodiment shown in FIGS. 6 to 14.
Whereas the connector disclosed in British Pat. No. 1586001 avoids the problem of blind assembly, it can still impart some shear stresses in the fibres if the vertical surfaces defined by the other limbs of the L-shaped blocks do not mate over substantially their entire surfaces. Further, this device suffers from the problem that moulding of the blocks is a relatively complex operation in requiring the provision of bores in the other limbs. Moreover, except in the more complex and hence more difficult to mould version, there is no adequate provision to prevent separation of the assembled blocks in a direction parallel with the axis of the fibres.